The present invention generally relates to handling of electronic parts or components, and more particularly, to a part mounting apparatus to be utilized for attracting and mounting electronic parts or components onto a printed circuit board and the like.
Conventionally, in the case where electronic parts are to be mounted on a printed circuit board, it has been a general practice to attract the electronic part onto an attracting or suction nozzle at a part supply position, and then to displace the attracting nozzle to a recognizing position so as to be able to recognize a projected shape of the attracted electronic part in a perpendicular direction or a flat or top plan shape thereof by a shape and position recognizing camera, with simultaneous recognition of the attracted position, and thereafter, to move the attracting nozzle to a position confronting a part mounting position of a printed circuit board with respect to the electronic part having a proper shape so as to correct the amount of positional deviation in the attracting position for mounting the electronic part at a predetermined position on the printed circuit board.
In the above procedure, since the flat or top plan shape of the electronic part is recognized before attaching, and defects, for example, bending of leads in a horizontal direction, breakage, chipping, etc. are detected, only defect free electronic parts will be mounted on the printed circuit board, and thus, there is no possibility that an entire printed circuit board undesirably becomes useless due to the attaching of a single defective electronic part.
However, in the known electronic part mounting apparatus as described above, there are such problems that, for example, where there is bending of the leads in a perpendicular direction, such a bending can not be detected, resulting in rising of a part of the leads when the leads are mounted on the printed circuit board, and thus, generation of a defect due to faulty connection between the electrodes of the printed circuit board and the leads can not be prevented. Particularly, in recent years, bending of leads in horizontal and perpendicular directions is apt to take place since leads tend to be narrow in width and thin because of an increase in the number of leads, so that solving of the above disadvantage is a very important problem.
In connection with the above, there has also previously been proposed and assigned to the same assignee as in the present invention, another part mounting apparatus in which a plurality of light projecting means and recognizing cameras are provided around four sides of the part travelling passage so as to confront each other so that the shape of the part in the perpendicular direction can also be recognized, but since such an arrangement requires a plurality of light projecting means and recognizing cameras, an increase in cost undesirably occurs, while due to the fact that only the projected image can be recognized, the amount of information available thereby is limited.